1. Field of the Invention
The present invention is related generally to a polarized electromagnetic relay, and more particularly to a relay including a coil member carrying an excitation winding and having two coil flanges and at least one axially extending through cavity. At least two armature contact tongues are arranged inside the coil member essentially parallel to the axis thereof, the armature contact tongues being seated at one side of the coil member in region of a first of the coil flanges. A plurality of stationary, cooperating contact elements serve as pole pieces and correspond in number to the number of contact tongues. The cooperating contact elements are in a region of a second of the coil flanges and are arranged opposite one another in respective pairs. The pairs of contact elements enclose a free end of corresponding ones of the contact tongues between them thereby forming working air gaps. A permanent magnet arrangement to which the pole pieces are coupled is provided so that the pole pieces of each and every pair are oppositely polarized.
2. Description of the Related Art
A relay of the foregoing type is disclosed, for example, in German published application No. DE-A-29 31 409. The relay includes two contact tongues and the contact tongues are seated in common in a coil flange in an exemplary embodiment therein and, as such, have their principle planes in one plane next to one another. The pole pieces are also arranged in pairs in a plane parallel to the plane of the contact tongues. A common, two-pole permanent magnet serves as a pre-magnetization means for both pole piece pairs. After the through-connection of a contact tongue, there is a risk that the magnetic circuit will close via this through-connected tongue and that the electromagnetic excitation is no longer sufficient under certain circumstances for switching the second contact unit. Additional measures are therefore provided in the known relay to improve synchronous switching of both contact tongues. For example, both contact tongues are enveloped with a common plastic part for the purpose of parallel guidance. Moreover, to fix the pole pieces in their respective, common plane, the pole pieces are additionally already enveloped in common before assembly. All of these measures require additional work steps and materials yet completely synchronous switching is nonetheless not guaranteed because of the unavoidable tolerances or variations.